Press Right, Left, Right, Left, Right, L2, R2, Start(2). The code Right, Left, Right, Left, Right, L2, R2, X(2) may also be used. Press Start to return to normal. You can fly around the city without being limited to the roads. Flight mode controls are:

R1: Altitude up
R2: Altitude down
L1: Propel forward
L2: Propel backward
Up: Look up
Down: Look down
Left: Turn left
Right: Turn right